Semiconductor memories (e.g. dynamic random access memory (DRAM)) can include memory cells that have a capacitor to store charge. The capacitor is typically a metal-insulator-metal (MIM) structure in which the insulator stores the charge for the cell. The state of the memory cell can be changed (e.g. from 0 to 1 or 1 to 0) by charging or discharging the capacitor.
It is desirable to reduce the size of individual memory cells to increase memory density thereby increasing potential memory storage. One way to reduce the size of individual memory cells is to increase the dielectric constant (K) of the insulator materials in the capacitors. A material with a higher dielectric constant can store more charge per unit volume, thereby reducing the amount of material needed to achieve a desired amount of charge.
Several materials have high dielectric constants. For example, titanium oxide potentially has a dielectric constant of over 90. However, different crystal phases of titanium oxide have different dielectric constants, and titanium oxide layers often have dielectric constants much lower than is desirable. Thus, what is needed are techniques for increasing the dielectric constant of deposited layers.